Process for separating mixtures of liquids.



suns arena oriucn.

ABRAM GoLonE'rz, or BERLIN, GERMANY, ASS'IGNOR or ONE-HALF T0 BEBNHARD BENEDIX, or HAMBURG, GERMANY.

PROCESS FOR SEPARATING MIXTURES OF LIQUIDS.

1 79,004. Ho Drawing.

To all whom it may concern:

Be it known that I, AnnAM GoLou'nr z, subject of the Emperor of Russia, residing at 132 Linienstrasse, Berlin, Germany, have invented certain new and useful Improvements in Processes for SeparatingMIXtures of Liquids, of which the following is a specification.

The present invention relates to mprovements in the process of separatlng mixtures of liquids into their components by f ractional distillation, the object of the present invention being to enable the components of such mixed liquids to be separated, winch it was hitherto irn 'ossible to separate by ordinary fractiona distillation, such as mixtures in which the boiling points of the components closely approximate each. other or in which two of the components form a binary homogeneous mixture of minimum boilin point.

In ttempting by fractional distillation to separate a mixture of an alcohol and a hydrocarbon, which form a binary homogeneous mixture of minimum boiling point, it has been proposed to add water in amount just suiiicient to distil over as a heterogeneous mixture with the whole of the hydrocarbon, leaving more or less pure alcohol. If, however, too much water is added, the binary homogeneous alcohol-water l'IllX- ture is also formed and part of the alcohol is thus lost on distilling. If, on the other hand, insufficient water is added, the whole of the hydrocarbon will not distil over. It 1s therefore very difficult to carry out this separation. It has also been proposed to sepa rate a bina homogeneous mixture of minimum boiling 'oint by adding a third liquid, immiscible 1n the binary mixture, in

sufiicient quantity to distil over as a ternary heterogeneous mixture with the two components to be separated, part of one of the components remaining behind in the still,- but m this case the other part of this component is lost, being carried over in the ternary mixture on distllling.

It may be stated here that a heterogeneous mixture is a mixture of two or more immiscible liquids whose vapor pressure is equal to the sum of the vapor pressures of the components, which is equal to the atmosph'eric pressure at a temperature lower than the boiling point of any of the components, so that the mixture boils at a temperature Specification of letters iatent.

Application filed AligllSt 16, 1912. Serial N0. 715,491.

i atented Nov. 18 19153.

lower than any of the oomponehtsn The oomposition of the vapor of a heterogeneous mixture does not depend upon the ratio of the components in the mixture but is always constant and the mixture boils at a constant temperature. A homogeneous mixture, on the contrary, is a mixture of two more miscible liquids whose vapor pressure is less than the sum of the Vapor pressures of the components, so that the mixture boils at a temperature which is not necessaril' lower than the boiling point of all the comdhneiits. The vapor of a homogeneous mixture contalns the components in the same ratio as the mixture and the mixture boils at a temperature dependent upon the ratio of the components.

The boilin point of a homogeneous iriiie ture usually lies between the boiling points ofthe components for all proportions of the components in the mixture. When, however, the boiling point of a homogeneous mixture is below the boiling oint of all the components, which occurs w 1811 the components are present in certain definite proportions, this-mixture is termed a mixture of minimum boilin point. I

According to are present invention a 1i uid is added to the mixture to be separate in -such quantity and such as to form a binary homogeneous mixture of minimum boiling point with one component only of the ori nal mixture, and the boiling point of te binary homo eneous mixture must be lower than the boi ing oint of any of the components of the or ginal mixture and lower than the boiling point of their mixture. The added liquid must not form a binary homogeneous mixture of minimum boiling point with more than one component of the original mixture but should be miscible in the other components so that the resulting mixture is homogeneous,

The following example is given of the method of separating the two components A and B of a binary homogeneous mixture of minimum boiling point 0: according to the present invention.

To the mixture the requisite quantit of a third liquid C is added which will onn" a binary homogeneous mixture with the component A of minimum boiling point {5. The boilin point Bmust be lower t an the boiling point (2. Moreover, the third liquid homogeneous mixture of minimum" boiling point with the other component B. The

third liquid vC should be miscible with the component B so as to form a homogeneous mixture.

If the whole mixture containing the three liquids A, B and G referred to is then subjected to fractional distillation, the component A. of the original mixture andthe added liquid C will be carried over at the corresponding boiling point (5. After com-- .pletion of the distillation the other component B of the original mixture remains in nearly pure condition in the flask as residue.

The distillate A C that passed off the flask ma then be separated in the sameway by 'ad ing a new liquid D which will form a homogeneous mixture of minimumbinary boiling point with the liquid 0 under the tion is carried out.

aforementioned conditions. In this manner the second component A of the original mixture may be separated. In the same manner the separation of mixtures of liquids having boiling points not far removed rom one another may be effected. The following examples will show how the process according to the present invenmethylalcohol wilL pass ofi at 59 C. as

distillate, whereas the other components of the light oil will remain in the residue. The mixture of benzene and methyl-alcohol may be separated into aqueous methyl-alcohol and benzene by adding water to the mixture. The mixture of benzene and methylalcohol may, however, also be separated by adding1 such quantity "of bisulfid of carbon, that t e proportion of the latter to the methyl-alcohol is 7' to 1. In this roportion the bisulfid of carbon forms with the methyl alcohol a binary homogeneous mixture having the 'minimum boiling point of 375, whereas the bisulfidof carbon will not form J such a mixture with the benzene. If the new mixture formed is subjected to distillation the bisulfid of carbon and methyl-alcohol will pass OR at the temperature of 375 and form two separate layersin the distillate.

In the distilling apparatus pure benzene remains as residue.

Example II: 13.5 parts of methyl-alcohol 186.5 parts of acetone form a binary homogeneous mixture having the minimum boiling point of 55. For separating such mixture, 256.5 parts bromethylene (b. p. 38) are added. When distilling this new mixture the whole of the methyl-alcohol passes over together with the bromethylene by forming a binary homogeneous mixture having the minimum boiling point of 35 in theproportion of 1 to 19. In'the residue pure acetone remains which does not form a homogeneous mixture of minimum boiling point with bromethylene.

I claim 1. The improved process of separating the components of a mixture of liquidswhich consists in adding to the mixture such a liquid in such quantity that it forms a binary homogeneous mixture of minimum boiling point with one of said components only, said minimum boiling point being lower than the boiling point of any of such components and lower than the boiling point of their mixture, and in thereupon fractionately distilling the whole.

2. The improved process of separating the components of a mixture of liquids which consists in adding to the mixture 9. liquid, which is miscible with said components so as to form a homogeneous mixture, in such quantity and such, that it forms a binary homogeneous point with one of said components only, said minimum boiling point being lower than the boiling point of any of such com.- ponents and lower than the boiling oint of their mixture, and in thereupon fiactionately distilling the whole.

3. The improved process of separating the two components of a binary mixture which consists in adding a third liquid thereto in such quantity and such that it forms a binary homogeneous mixture of minimum boiling point with one of said components only, said minimum boiling point being lower than'the boiling point of either'of said components and lower than the boiling point of their mixture, and in thereupon fractionately distilling the whole.

4, The improved process of separating'the two components of a binary mixture which consists in adding a third liquid thereto mixture of minimum boiling miscible with both said components so as to form a homogeneous mixture, said third liquid being such that and being added in such quantity that it forms a binary homogeneous mixture of minimum boiling point with one of said components only, said minimum boiling point bein lower than the boiling point of either 0 said components and lower than they boiling point of their mixture, and in thereupon fractionately distilling the whole. 1

'5. 'Ihe'improved process of separating the two components of a binary homogeneous mixture of minimum boiling point which consists in adding a third liquid thereto in such quantity and such that it forms a binary homogeneous mixture of minimum boiling point with one of said components only and of lower boiling point than the minimum boiling point of the mixture of said components, and in thereupon fractionately distilling the whole.

6. The improved process of separating the two components of a binary homogeneous mixture of minimum boiling point which consists in adding a third liquid thereto miscible with both of said components, said third liquid being such that and being added in such quantity that it forms a binary homo- 15 and in thereupon fractionately distilling the 20 whole. 0

In testimon whereof I aflix my slgnature in presence 0 two witnesses.

ABRAM GOLODETZ.

Witnesses HENRY HASPER, ARTHUR Sonnonmuz. 

